Lung cancer is the leading cause of cancer-related death globally. For early-stage non-small cell lung cancer (NSCLC), a surgical resection is one of the choice for treatment of early-stage non-small cell lung cancer (NSCLC).1,2 Although surgical resection remains the mainstay of the treatment and provides the best chance for survical,3-6 the reported failure rate in stage I NSCLC ranges from 27% to 38%,5-9 and about 90% cancer deaths are associated with tumor recurrence or metastasis.8-12 Many randomized clinical trials have evaluated the role of adjuvant chemotherapy in patients with resected stage I NSCLC,13-15 and tried to identify patients with higher risks of recurrence or poor prognosis after surgical resection. However, the results remain controversial.
It was found in the prior art references, the patients with stage I NSCLC had relative good outcome after surgical resection.3-6 However, the survival in patients with recurrence after surgical resection was poor.8-12 Adenocarcinoma was the most common histologic subtype of NSCLC in most countries.28,29 Furthermore, adenocarcinoma increased in both sexes in the past decades while squamous cell carcinoma had decreased.28 Although postoperative adjuvant chemotherapy was widely accepted in locally advanced NSCLC, the role of adjuvant chemotherapy in early-stage NSCLC remained to be determined. Many reports in the literature tried to identify poor prognostic factors in patients with stage I NSCLC for adjuvant therapy.13-15 Furthermore, it was discovered in several current clinical trials that histologic subgroups had different outcomes to targeted therapy and newer chemotherapy.30-33
Therefore, to identify subgroup of early-stage lung adenocarcinoma patients with higher risks for histology-based treatment is important and still desirous in the early stage.